JPH0441238Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a starting device for a small engine equipped with a diaphragm carburetor.

(Prior Art) In general, a small engine equipped with a diaphragm type carburetor requires filling the fuel chamber of the carburetor with fuel before starting the engine. As disclosed in the publication, a manual pump is installed in the fuel passage from the fuel tank to the fuel valve, and at the same time the diaphragm of the carburetor is pushed up to forcefully open the fuel valve at the inlet of the fuel chamber, and at the same time, the overflow valve is opened. By installing a takera lever and operating the takera lever at the same time as the manual pump operation before starting the engine, it is possible to smoothly introduce fuel into the fuel chamber and to check that the fuel chamber is filled with fuel from fuel overflow. configured to detect.

In addition, in order to make it easier to start the engine, it is desirable to supply a rich mixture at the time of starting, but even if the fuel chamber is filled with fuel, the amount of fuel supplied from the nozzle will match the operating conditions after starting. Therefore, in order to supply the desired rich air-fuel mixture to the engine, it is necessary to further limit the amount of intake space by operating the choke valve.

(Problems with the Prior Art) However, with the above-mentioned starting device, it is necessary to operate both the manual pump and the takera lever at the time of starting, which requires both hands and is cumbersome to handle. Furthermore, after filling the fuel chamber with fuel, it is necessary to perform a choke operation to obtain a rich mixture for starting, and these operations are extremely troublesome.

(Purpose) The object of the present invention is to provide a small engine that does not require any special starting operation and can be started simply by recoil operation.

(Structure of the invention) The structure of the invention made to achieve the above object is to connect the fuel chamber of the carburetor to a negative pressure pump that operates in conjunction with a recoil starter, and connect the fuel chamber to a negative pressure pump in the middle of the connection. In addition to providing a check valve that allows flow in this direction, a starting fuel chamber is provided between the check valve and the negative pressure pump, with the inlet side of the passage opening at the lower part of the chamber and the outlet side opening at the upper part of the chamber. At the top of the starting fuel chamber, a starting air-fuel mixture passage that communicates with the intake passage downstream of the throttle valve is opened, while at the bottom of the starting fuel chamber, intake air is connected to the suction amount of the negative pressure pump. This opens a starting air passage having a constriction portion with a small volume.

(Function) When starting the engine, when the recoil starter is pulled, the negative pressure pump operates in conjunction with the recoil starter, and the operation of this negative pressure pump introduces negative pressure into the starting fuel chamber, and the starting air passage Aspirate a small amount of air from the Further, the remaining negative pressure is further introduced into the fuel chamber through a check valve, and the air and fuel accumulated in the fuel chamber are sucked into the starting fuel chamber. Furthermore, as the pressure inside the fuel chamber becomes negative, the diaphragm moves upward, opening the fuel valve and sucking fuel from the fuel tank into the chamber.

Then, the fuel sucked into the starting fuel chamber by the subsequent operation of the recoil starter mixes with the air sucked in from the starting air passage, and is sucked into the negative pressure pump and returned to the fuel tank.

In addition, the fuel drawn into the starting fuel chamber from the fuel chamber is introduced from the lower entrance of the starting fuel chamber toward the top, which allows the accumulated air in the starting fuel chamber to be efficiently discharged and quickly fills the starting fuel chamber with fuel. let

In addition, when the recoil starter is operated, the engine's intake negative pressure generated in the intake passage simultaneously with the operation of the negative pressure pump acts on the starting fuel chamber through the starting mixture passage, and is stored in the chamber. Foamy fuel is sucked into the intake passage, and together with the air flowing through it, it creates a rich mixture for starting.

When the engine starts, the operation of the recoil starter is stopped, so the suction action of the negative pressure pump disappears, and the check valve closes, cutting off the fuel chamber and the starting fuel chamber, but fuel remains in the starting fuel chamber. Therefore, this fuel is foamed by the air flowing in from the starting air passage, becomes foamy fuel, and is ejected into the intake passage for a while, creating a rich mixture with the air flowing there, which is then sucked into the engine. , perform warm-up operation smoothly.

(Example) An example of the present invention will be specifically described based on the drawings.

Fig. 1 is a side view of an engine using the starting device of the present invention, Fig. 2 is a longitudinal cross-sectional view showing the diaphragm type carburetor (cross-sectional view taken along the line X-X in Fig. 1), and Fig. 3 is the same as that shown in Fig. 1. FIG. 2 is an explanatory diagram of an embodiment of the starter device of the present invention illustrated by a sectional view taken along the line Y-Y of FIG.

1 is a diaphragm type vaporizer. An intake passage 3 is provided in the carburetor body 2 of this diaphragm type carburetor 1.
is provided through the intake passage 3, and a throttle valve 4 faces the intake passage 3 from above so as to be movable forward and backward. The throttle valve 4
A main nozzle 5 is opened in the bottom wall of the lower intake passage 3, and the tip of a jet needle 6 that hangs down from the throttle valve 4 is inserted into the main nozzle 5. The main nozzle 5 communicates with a fuel chamber 8 via a fuel orifice 7.

The diaphragm carburetor 1 also includes a pulsation pump 10 that is operated by the pulsation of the engine 9. This pulsating pump 10 has a suction side fuel passage 1
1 and the discharge side fuel passage 12 are connected, and the suction side fuel passage 11 is connected to the connection port 14 to the fuel tank 13.
The discharge side fuel passage 12 is connected to the fuel chamber 8 through the fuel tank.

The fuel chamber 8 has a bottom wall formed by a diaphragm 15, and the inlet of the fuel chamber 8 of the fuel passage 12 is connected to the diaphragm 15 to connect the fuel passage 12, that is, to connect the pulsating pump 10 and the fuel chamber. A fuel valve 16 is provided that operates to disconnect and disconnect the fuel cell 8. A lever 18 having a support shaft 17 is disposed between the fuel valve 16 and the diaphragm 15, and the lever 18 has one side connected to the fuel valve 16 around the support shaft 17, and the other side connected to the diaphragm 17. It is connected to 15. Therefore, when a strong negative intake pressure acts on the fuel chamber 8 through the main nozzle 5, the diaphragm 15 moves upward and the lever 18 is moved to introduce fuel from the pulsating pump 10 into the fuel chamber 8 through the fuel passage 12. to hold the fuel valve 16 in the open position. Furthermore, when the strong negative pressure in the fuel chamber 8 disappears due to the introduction of fuel into the fuel chamber 8, the fuel valve 16 is activated by the compression spring 1 which engages the lever 18.
The biasing force 9 blocks the fuel passage 12 to prevent the introduction of fuel into the fuel chamber 8 .

Further, the fuel chamber 8 is connected through a passage 20 to a negative pressure pump 22 that operates in conjunction with a recoil starter 21 of the engine 9. This passage 20
A starting fuel chamber 23 is provided in the middle of the fuel chamber 23, the inlet side of which opens to the lower part of the chamber, and the outlet side of which opens to the upper part of the chamber. A check valve 24 is provided that allows the flow of water and is opened only by the suction negative pressure of the negative pressure pump 22.

A starting air mixture passage 25 that communicates with the intake passage 3 downstream of the throttle valve 4 is opened in the upper part of the starting fuel chamber 23, and the intake air amount is set to be smaller than the suction amount of the negative pressure pump in the lower part. A starting air passage 26 having a constricted portion is opened, and a check valve 27 is disposed in the starting air mixture passage 25 to prevent blowback due to pulsation of intake negative pressure.

The negative pressure pump 22 is attached to a recoil starter case 28, with its operating rod 29 passing through the case 28. This operating rod 2
Reference numeral 9 denotes a starting pulley 3 disposed within the case 28.
It moves forward and backward by intermittently contacting a cam 31 formed on the outer circumferential surface of 0. The base end of the actuating rod 29 is connected to a pump diaphragm 32, and the pump diaphragm 32 is oscillated by the forward and backward movement of the actuating rod 29 by the cam 31 of the starting pulley 30. The chamber 33 is expanded and contracted.
Further, a suction passage 36 and a discharge passage 37 are connected to this pump chamber 33 via check valves 34 and 35, respectively. is connected to the fuel tank 13. Therefore, when the pump chamber 33 expands due to the movement of the pump diaphragm 32, the pump chamber 33 becomes in a negative pressure state and the check valve 3
4 opens and the starting fuel chamber 23 and check valve 24 open.
The fuel in the fuel chamber 8 is sucked into the pump chamber 33 through. At the same time, a small amount of air is sucked into the starting fuel chamber 23 from the starting air passage 26 and mixed with the fuel. Next, when the pump chamber 33 contracts, the inside of the pump chamber 33 becomes in a positive pressure state, and the check valve 35 is opened to return the fuel in the pump chamber 33 to the fuel tank 13 via the discharge passage 37. 39 is a rope that rotates the starting pulley 30, and 40 is a rope handle.

The operation of the embodiment configured as above will be explained.

When starting the engine, when the starting pulley 30 is rotated by pulling the rope handle 40,
Since the cam 31 intermittently contacts the actuating rod 29 of the negative pressure pump 22 during the rotation of the pulley 30, the actuating rod 29 moves back and forth each time, and the negative pressure pump 22 is driven. This negative pressure pump 22
By the operation of , a negative pressure is introduced into the starting fuel chamber, and a small amount of air is sucked from the starting air passage. Further, the remaining negative pressure is further introduced into the fuel chamber 8 through the check valve 24, and the air and fuel remaining in the fuel chamber 8 are sucked into the starting fuel chamber. Furthermore, when the inside of the fuel chamber 8 becomes negative pressure, the diaphragm 15 moves upward, and the fuel valve 16 opens, allowing fuel to be sucked into the chamber 8 from the fuel tank 13.

Then, the fuel sucked into the starting fuel chamber 8 by the subsequent operation of the recoil starter 21 mixes with the air sucked in from the starting air passage.
It is sucked into the negative pressure pump and returned to the fuel tank 13.

Further, the fuel sucked into the starting fuel chamber 23 from the fuel chamber 8 is introduced from the lower inlet of the starting fuel chamber 23 toward the upper side, which improves the discharge of the air accumulated in the fuel chamber 23 and drains the fuel. Fill quickly.

In addition, when the recoil starter 21 is operated, the engine intake negative pressure generated in the intake passage 3 simultaneously with the operation of the negative pressure pump 22 acts on the starting fuel chamber 23 via the starting mixture passage 25. The foamy fuel stored in the chamber 23 is sucked into the intake passage, and together with the air flowing therein, a rich air-fuel mixture for starting is generated.

When the engine starts with the rich mixture,
Since the operation of the recoil starter 21 is stopped, the suction action of the negative pressure pump 22 is eliminated, and the check valve 24
closes, shutting off the fuel chamber 8 and the starting fuel chamber 23, but since fuel remains in the starting fuel chamber 23, this fuel is bubbled by the air flowing in from the starting air passage 26. The fuel becomes foamy fuel and is ejected into the intake passage 3 for a while, producing a rich mixture with the air flowing there, which is then sucked into the engine to smoothly warm up the engine.

When the fuel in the starting fuel chamber 23 is consumed, a mixture of normal concentration is generated by ejecting fuel only from normal nozzles, and the engine continues to operate.

Further, in the above embodiment, an example was explained in which the present invention was applied to a diaphragm type carburetor equipped with a sliding throttle valve, but the effect will not be obtained even if the present invention is applied to a carburetor equipped with a butterfly type throttle valve. The same is true.

(Effects) As detailed above, according to the present invention, when starting the engine, by simply pulling the recoil starter, the air accumulated in the fuel chamber of the diaphragm carburetor is removed, the chamber is filled with fuel, and the engine is started at the same time. Since it is possible to supply a rich mixture to the engine, it is possible to completely omit the manual pump operation, take-off operation, and choke operation that were required for conventional engines equipped with diaphragm carburetors, making it easier to start this type of engine. can be done extremely easily.

[Brief explanation of the drawing]

Fig. 1 is a side view of an engine using the starting device of the present invention, Fig. 2 is a longitudinal cross-sectional view showing a diaphragm carburetor (cross-sectional view taken along the line X-X in Fig. 1), and Fig. 3 is the same as that shown in Fig. 1. FIG. 3 is an explanatory diagram of an embodiment of the starter device of the present invention, which is explained using a sectional view taken along the line Y-Y of FIG. 1... Diaphragm carburetor, 3... Intake passage, 8... Fuel chamber, 20... Passage, 21... Recoil starter, 22... Negative pressure pump, 23... Fuel chamber for starting, 24... Reverse Stop valve, 25...Starting air mixture passage, 26...Starting air passage.

Claims (1)

[Scope of utility model registration request] In an engine equipped with a diaphragm carburetor, a check valve connects the fuel chamber of the carburetor to a negative pressure pump that operates in conjunction with a recoil starter, and allows flow from the fuel chamber toward the negative pressure pump. At the same time, a starting fuel chamber is provided between the check valve and the negative pressure pump, with the inlet side of the passage opening at the lower part of the chamber and the outlet side opening at the upper part of the chamber. opens the starting air-fuel mixture passage that communicates with the intake passage downstream of the throttle valve, and has a throttle part at the bottom of the starting fuel chamber where the amount of intake air is set to be smaller than the suction amount of the negative pressure pump. An engine starting device equipped with a diaphragm carburetor that opens a starting air passage.